I am not sure why you are so convinced there is "denominational bias." For one thing, there are people of many denominations posting here. I think maybe you are projecting from your own experience. It is biased to assume that all of us here have a "denominational bias."
Why would you read Shelby Spong or Matthew Fox? Spong denies every essential of the Christian faith. The man is apostate. And Matthew Fox is a New Ager who says we can all be "christs."
I read 'Born of a Woman' by Spong as an assignment in an Episcopal study group I once participated in. I read Matthew Fox (Original Blessing) for the same reason. Spong not only denies every essential of the Christian faith, I'm convinced he is an atheist.
Bishop John Shelby Spong:
# 1. Theism, as a way of defining God, is dead. God can no longer be understood with credibility as a Being, supernatural in power, dwelling above the sky and prepared to invade human history periodically to enforce the divine will. So, most theological God-talk today is meaningless unless we find a new way to speak of God.
# "2. Since God can no longer be conceived in theistic terms, it becomes nonsensical to seek to understand Jesus as the incarnation of the theistic deity. So, the Christology of the ages is bankrupt."
# (pp. 453-454, 'Here I Stand,' John Shelby Spong, Twelve Theses,A Bishop Speaks to Believers in Exile,A Call for a New Reformation.)
You have a good point about my 'denominational bais' comment.